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<a href="intro.html"><h2>SQLite C Interface</h2></a><h2>Database Connection Configuration Options</h2><blockquote><pre>#define SQLITE_DBCONFIG_LOOKASIDE       1001  /* void* int int */
#define SQLITE_DBCONFIG_ENABLE_FKEY     1002  /* int int* */
#define SQLITE_DBCONFIG_ENABLE_TRIGGER  1003  /* int int* */
</pre></blockquote><p>
These constants are the available integer configuration options that
can be passed as the second argument to the <a href="../c3ref/db_config.html">sqlite3_db_config()</a> interface.</p>

<p>New configuration options may be added in future releases of SQLite.
Existing configuration options might be discontinued.  Applications
should check the return code from <a href="../c3ref/db_config.html">sqlite3_db_config()</a> to make sure that
the call worked.  The <a href="../c3ref/db_config.html">sqlite3_db_config()</a> interface will return a
non-zero <a href="../c3ref/c_abort.html">error code</a> if a discontinued or unsupported configuration option
is invoked.</p>

<p><dl>
<dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
<dd> This option takes three additional arguments that determine the
<a href="../malloc.html#lookaside">lookaside memory allocator</a> configuration for the <a href="../c3ref/sqlite3.html">database connection</a>.
The first argument (the third parameter to <a href="../c3ref/db_config.html">sqlite3_db_config()</a> is a
pointer to a memory buffer to use for lookaside memory.
The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
may be NULL in which case SQLite will allocate the
lookaside buffer itself using <a href="../c3ref/free.html">sqlite3_malloc()</a>. The second argument is the
size of each lookaside buffer slot.  The third argument is the number of
slots.  The size of the buffer in the first argument must be greater than
or equal to the product of the second and third arguments.  The buffer
must be aligned to an 8-byte boundary.  If the second argument to
SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
rounded down to the next smaller multiple of 8.  The lookaside memory
configuration for a database connection can only be changed when that
connection is not currently using lookaside memory, or in other words
when the "current value" returned by
<a href="../c3ref/db_status.html">sqlite3_db_status</a>(D,<a href="../c3ref/c_config_getmalloc.html#sqliteconfiglookaside">SQLITE_CONFIG_LOOKASIDE</a>,...) is zero.
Any attempt to change the lookaside memory configuration when lookaside
memory is in use leaves the configuration unchanged and returns
<a href="../c3ref/c_abort.html">SQLITE_BUSY</a>.</dd></p>

<p><dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
<dd> This option is used to enable or disable the enforcement of
<a href="../foreignkeys.html">foreign key constraints</a>.  There should be two additional arguments.
The first argument is an integer which is 0 to disable FK enforcement,
positive to enable FK enforcement or negative to leave FK enforcement
unchanged.  The second parameter is a pointer to an integer into which
is written 0 or 1 to indicate whether FK enforcement is off or on
following this call.  The second parameter may be a NULL pointer, in
which case the FK enforcement setting is not reported back. </dd></p>

<p><dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
<dd> This option is used to enable or disable <a href="../lang_createtrigger.html">triggers</a>.
There should be two additional arguments.
The first argument is an integer which is 0 to disable triggers,
positive to enable triggers or negative to leave the setting unchanged.
The second parameter is a pointer to an integer into which
is written 0 or 1 to indicate whether triggers are disabled or enabled
following this call.  The second parameter may be a NULL pointer, in
which case the trigger setting is not reported back. </dd></p>

<p></dl>
</p><p>See also lists of
  <a href="objlist.html">Objects</a>,
  <a href="constlist.html">Constants</a>, and
  <a href="funclist.html">Functions</a>.</p>
